The effect of ovariectomy on hemodynamic functions and the level of nitric oxide metabolites in the heart of rats

Background. A higher prevalence of cardiovascular disorders has been observed in women after menopause. This study aimed to determine the long-term effects of ovariectomy on hemodynamic functions and the level of nitric oxide metabolites (NOx) in the heart tissue of ovariectomized rats.

Methods. Fourteen female Wistar rats were divided into two groups (n=7 in each group) of control and ovariectomized (OVX). OVX rat model was induced using the two dorsolateral skin incision method. Cardiac hemodynamic function indices, including the left ventricular developed pressure (LVDP), peak rate of positive changes in the left ventricular pressure (+dp/dt), and peak rate of negative changes in the left ventricular pressure (-dp/dt) were measured at the time of systole in hearts after 11 months of the ovariectomy. Serum and left ventricular levels of NOx were measured at the end of the study.

Results. At the end of the study, OVX rats had lower LVDP (19%, P=0.001), +dp/dt (30%, P<0.001) and -dp/dt (23%, P=0.004) than control group. In addition, the OVX group had lower serum NOx levels (30%, P=0.021) compared to the control group; heart tissue NOx was also lower by 31% in the OVX rats, but it was not statistically significant (P=0.056).

Conclusion. Long-term ovariectomy disrupts cardiac hemodynamic function in ovariectomized rats, which is associated with decreased NOx levels in serum.

Practical Implications. Our findings indicated impaired cardiac function following long-term estrogen deficiency in OVX rats. These results can be used to prevent and treat the cardiovascular disease in post-menopausal women. However, these results need to be confirmed in humans.